1. Field of the Invention
The present invention relates to a connector apparatus for memory cards, and more particularly, to a connector apparatus having multiple storage decks and an improved mechanism for connecting the respective contacts of each storage deck to a printed circuit board.
2. Description of the Prior Art
Plate-like integrated circuit cards, commonly referred to in the art as "memory cards", have become increasingly popular for use in notebook, laptop and desktop computers, as well as other consumer products. Standard specifications from the Personal Computer Memory Card International Association (PCMCIA) and the Japan Electronic Industry Development Association (JEIDA) have helped to expand this relatively new industry. Other standard specifications have been developed by the Joint Electron Device Engineering Council (JEDEC). Although commonly referred to as "memory cards," these cards are by no means limited to data storage applications. For example, some cards may perform various I/O functions for modem and local area network applications.
Currently, the PCMCIA/JEIDA standard cards incorporate a 68-pin female connector at one end, and are available in three formats. Type I houses SRAM, PSRAM, MROM, OPTROM, and flash memory chips and only performs memory functions. Type I cards have a thickness of 3.3 mm. Type II cards perform I/O functions for modem and local area network (LAN) applications. The side edges of Type II cards are 3.3 mm thick, however, the main body of the cards is 5.0 mm thick. Type III cards are really not "cards," but rather 1.8 inch hard disk drives having a 10.5 mm thick housing. Again, however, these cards are equipped with outside edges of 3.3 mm.
Given the increasing popularity of these "memory cards," a need has arisen for suitable connector devices for connecting these cards to printed circuit boards in host devices, such as notebook, laptop and desktop computers. A number of connector devices have appeared in the prior art. Prior art connector devices typically comprise some sort of frame or housing into which a memory card may be inserted. A contact header with an array of pin contacts is provided at the far end of the housing to connect with a corresponding contact array disposed in the front end of the memory card. Typically, L-shaped pin contacts are employed in the connector to facilitate connection of each pin to a printed circuit board; one end of each pin extends into the storage space of the connector, while the other end extends downwardly, external to the housing, for soldering to the printed circuit board.
Many prior art connector devices employ an ejection mechanism having a slide plate that engages with the memory card, a rotatable lever mounted on the housing and coupled at one end to the slide plate, and a push rod coupled to the other end of the lever. To eject a memory card, the push rod is manually driven toward the contact header. Movement of the push rod toward the contact header is translated through the rotating lever into movement of the slide plate away from the contact header. As the slide plate moves away from the contact header, it engages with the memory card thereby disconnecting the memory card from the array of contacts on the header and urging the memory card backward out of the connector device.
Some connector devices have multiple storage decks. For example, U.S. Pat. No. 5,149,276 discloses a connector apparatus having upper and lower storage decks. Each deck has its own array of pin contacts. As is typical of prior art connector devices with multiple storage decks, L-shaped pins are employed in each deck. Thus, the external portions of both sets of pins extend downwardly for connection to a printed circuit board mounted underneath the connector apparatus. Of course, the upper set of contact pins must protrude further from the connector before extending downwardly to the printed circuit board so as to avoid interference with the lower set of contact pins. Each set of pins are connected to the printed circuit board by soldering.
Unfortunately, the use of L-shaped pins in each storage deck has proven to be disadvantageous when attempting to solder each set of contact pins to the same printed circuit board. In particular, it has been difficult to employ surface mount techniques to connect each set of contact pins to the circuit board. Consequently, high volume production of printed circuit boards with multiple storage deck connectors is difficult to achieve.
Generally, the upper and lower storage decks are separate units and are simply mounted on top of each other to form a dual storage deck apparatus. Unfortunately, because the L-shaped contact pins of the upper deck extend outward, effectively covering the contact pins of the lower deck, surface mount techniques for soldering the respective sets of contact pins to a circuit board are difficult; the contact pins of the upper storage deck prevent easy access to the contact pins of the lower deck.
One solution to this problem is to solder the contact pins of the lower deck to the circuit board in a first soldering step prior to mounting the upper storage deck. Once the lower storage deck is secure, the upper storage deck may be mounted on the lower storage deck, and the contact pins of the upper storage deck may be soldered to the circuit board in a second soldering step. Unfortunately, however, the second soldering step can effect the hardened solder joints of the lower contact pins in such a way that stress may occur in the hardened solder joints, in components already attached to the circuit board, and in the circuit board itself. Moreover, if one of the lower contact pins breaks free during the second soldering step, resoldering is extremely difficult since the upper contacts are now in the way.